Answer:
third angle = (-6x + 161)°
Step-by-step explanation:
180° = (x)° + (5x + 19)° + third angle →
180° = (6x + 19)° + third angle →
180° – (6x + 19)° = (6x + 19)° + third angle – (6x + 19)° →
180° – (6x + 19)° = third angle →
180° + -(6x + 19)° = third angle →
180° + (-6x)° + (-19)° = third angle
180° – 6x° – 19° = third angle
(180° – 19°) – 6x° = third angle
161° – 6x° = third angle
third angle = 161 – 6x°
third angle = -6x° + 161°
third angle = (-6x + 161)°
B. (k+10f)(k-5f) you can tell in 2 ways. 1. if the second sign is neg then the signs in the factors are going to be one neg and one positive so that knocks out C and D. Then you look at the second term and since the 5 is positive then the 10 has to be positive so you end up with a positive 5kf.
The second way is to FOIL them out. When you check B you get

combine your like terms and you have your original expression of

Hope that helps
Answer:

Step-by-step explanation:
A regular polygon is a shape with equal sides and angles. Because of this, we can write the following equation to set two sides equal to each other:

Solving, we will get a in terms of b:

Now we can substitute a for (b+3) into our equation:

Therefore, the length of each side of this polygon is
.
Since the perimeter of the polygon consists of all five sides, the perimeter is:

Common ratio can be found by dividing the 2nd term by the first
r = 48/6
r = 8
an = a1 * r^(n-1)
n = term to find = 8
a1 = first number = 6
r = common ratio = 8
now we sub
a(8) = 6 * 8^(8-1)
a(8) = 6 * 8^7
a(8) = 6 * 2097152
a(8) = 12582912 <==